Arthritis Drug Fears Escalate

Thousands of Kiwi arthritis sufferers are taking a drug which New Zealand research suggests may carry as much risk of causing heart attacks and strokes as one that has just been withdrawn worldwide.

About 14,000 New Zealanders are on Celebrex, a pain-relieving Cox-2 inhibitor drug which preliminary data shows may be slightly more likely to cause circulatory problems than Vioxx, which was pulled from pharmacies this month.

Celebrex maker Pfizer is running a national ad campaign saying Celebrex is safe, and offering free samples of the unsubsidised drug.

"Just because two drugs are in the same class of medicines doesn't mean they will have the same make-up and the same outcomes," said Pfizer spokeswoman Suzanne Booth.

But preliminary figures from the Otago-based intensive medicines monitoring programme (IMMP) show adverse event rates of patients on Vioxx and Celebrex are very similar: 0.8% or 228 of 26,666 patients on Vioxx reported circulatory problems, compared with 1% (344) of the 32,000 patients on Celebrex.

Definitive results may never be known because the drugs were pulled from the New Zealand study and the IMMP threatened with closure.

Pfizer - which has reported a significant increase in Celebrex use since Vioxx was withdrawn - points to large-scale clinical trials to support its safety claims. In a recent US Food and Drug Administration-sponsored study of 1.4 million patients, those who received Celebrex showed no increased risk of cardiac events. It also found patients on Celebrex were significantly less likely to have cardiac events than those on Vioxx.

However, Christchurch School of Medicine general practice professor Les Toop said he was worried about the safety of all Cox-2 inhibitors, and believed there was no evidence to support Pfizer's safety claims.

He never prescribed the drugs because of the risks and advised other doctors to avoid putting new patients on it until the uncertainty had cleared up.

Toop's opinion was that it was appalling drug companies were allowed to take out large ads when the medicines were potentially dangerous. Only New Zealand and the US allowed such advertising. He said medicine safety authority Medsafe should warn prescribers of doubts over the drug's safety and advise caution over its use. The IMMP's former director Associate Professor David Coulter, shared Toop's concern. The IMMP has monitored Vioxx and Celebrex since they became available in New Zealand in 2000.

A 2003 report to the government's medicines adverse reactions committee noted preliminary findings that both drugs increased the risk of circulatory problems and had a high death rate, particularly in the elderly.

Coulter said both drugs appeared to have the same rates of heart complications. He was concerned by the continued use of Celebrex and questioned Pfizer's safety assurances. He said the Vioxx studies that led to the recall had not been done on Celebrex.

With increased resources, the IMMP could give a definitive finding within six months, Coulter said. But he said Medsafe last year indicated the Cox-2 inhibitors should no longer be a priority and instructed IMMP to stop monitoring both drugs.

Health Ministry spokeswoman Sharon Sime said the government was awaiting international data from drug manufacturers before making recommendations on the safety of the drugs. This could take a few weeks.

Coulter said while preliminary data lacked sufficient evidence for Medsafe to withdraw Celebrex - for example, it was unknown how many adverse events were exacerbated by patients' age - it was a mistake to stop intensive monitoring. Medsafe told the IMMP in May that funding was being withdrawn, and the future of the research and other medicines monitoring now hangs in the balance.

Medsafe confirmed IMMP's future was under discussion, but director Stuart Jessamine denied arthritis drugs had been removed from IMMP monitoring.

The potential closure of the IMMP - one of only two research units in the world collecting reports on all side effects in patients on a new or suspect drug - has alarmed the international scientific community.

In July, a group of internationally renowned doctors wrote an open letter to Health Minister Annette King in the British Medical Journal urging the government to continue and strengthen the IMMP.

"The IMMP should be seen as a cost-effective investment in the welfare of your people," it said.

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Disclaimer: The health information presented here has been written for the New Zealand health consumer. It is of a general nature and is only intended to provide a summary of the subjects covered. The information is not intended to be comprehensive or to provide medical advice to you. While all care has been taken to ensure the accuracy of the information, no responsibility or liability is accepted, and no person should act in reliance on any statement contained in the information provided. All health ailments should be treated by a qualified health professional.

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Disclaimer: The health information presented here has been written for the New Zealand health consumer. It is of a general nature and is only intended to provide a summary of the subjects covered. The information is not intended to be comprehensive or to provide medical advice to you. While all care has been taken to ensure the accuracy of the information, no responsibility or liability is accepted, and no person should act in reliance on any statement contained in the information provided. All health ailments should be treated by a qualified health professional. If you require additional information you can contact the healthy.co.nz naturopathic team on 0800 HEALTHY or email naturopath@healthy.co.nz